Heat treating apparatus



2 Sheets-Sheet 1 Filed May 17, 1950 FIG.

.FREDERIC O. HESS ATTORNEY.

June 21, 1955 F. o. HESS 2,711,309

HEAT TREATING APPARATUS Filed May 17, 1950 2 Sheets-Sheet 2 INVENTOR. FREDERIC O. HESS I0 ATTORNEY.

United States Patent 0 The present invention relates to heat treating machines, and more particularly to machines for automatically heating a predetermined length of the end of ,..z,111, o9 Patented June 21, 1955 Figure 2 is a view taken substantially on line '22' of Figure l showing a section through the furnace and a portion of the conveyor; and

Figure 3 isa'nenlarged'view of. o'nejo'f the magnetic work holders. j 7

Referring to Figure 1, there is a frame 1 for supporting a furnace 2 in'which the work W is heated. There mechanism serves to move the work'downwardly through: the furnace and to-discharge it for delivery to a point a bar, for example, to a temperature suitable for forging or some other metal working operation.

It is an object of the present invention to provide a machine for automatically heating the ends of elongated work pieces such as bars and the like to precisely a predetermined temperature for a predetermined portion of their length.

It is a further, and more particular, object of the is also provided additional framework, to be described below, upon which the parts of the conveyor mechanism, indicated generally 'at 3, is mounted; This conveyor upon which further'operations can be performed on it.

The furnace as shown in Figures 1 and 2 is mounted 5 on end and is formed of refractory blocks 5 that are backed up with sheet metal 6 in accordance with conventional furnace practice; The refractoryblocks are so, placed that there is provided a centrally disposed furnace'chamber 7 'havinga slot 8 in oneend thereof through which the work may project; This slotyextends also through the top and the bottom-of the furnace'so that work maybe moved vertically downward into the invention to provide a conveying mechanism to hold the work pieces to be heated rigidly and in anexact location while they are being moved through the furnace.

The machine of the present invention includes a vertically disposed furnace having a slot at one sideand openings at the top and bottom. The bars or other work to be heated are moved downwardly in front of the furnace with the ends to be heated passing through the opening in the top thereof. The furnace "is so de signed and the speed of the conveying mechanism is such that by the time the work is removed from the bottom of the furnace its temperature hasbeen raised to the desired value. The conveying mechanism for moving the work through the furnace consists of an endless chain passing over a series of guide sprockets. The chain is provided with a series of permanent magnets which serve furnace and out of the same to the point of discharge.

The-sides of the furnace, as best shown in Figure 2, comprise burner blocks 9forrning burners of a type that ar'edescribed in-Hess' 2,215,079, issued September 17,

- 1940. Each of theseburner blocks is formed with a cup-shaped depression 11 into the bottom of which extends a distributor 12 through which a combustible fuel mixture is discharged in a plurality of jets for burning along the surface of the cup. Theburning gases heat the surface'of the cup to incandescence so that radiant heat is projected toward the work to' heat the same.

The hot products-of combustion from the burners rise. vertically in the furnace and are discharged through the slot at thetop thereof through which the work is introduced. Each of'the distributors llis supplied by a pipe :13 that is connected-to a manifold 14; There are two of these manifolds, one for each side of the furnace, and they in" turn are supplied by a main supply pipe 15.

' Each of the pipes 13 has in ita manually adjusted valve to hold the work in position as it is moving to and from the furnace, as well as while it is being heated.

Means are provided to keep the magnets relatively cool as they are passing in front of the furnace to thereby prevent loss of magnetism- Each of the magnets is also immersed in a cooling fluid after the heatedwork has been stripped therefrom so that it will be at ambient temperature by the time it is ready to receive another piece of work to be heated. In some particularly severe applications where the work is heated to very high temperatures it may be necessary to raise the magnetism of the magnets to a standard level after each passage past the furnace. This may easily be done by placing a magnetizing apparatus adjacent to the path of travel of the magnets.

It is, therefore, a further and more specific object of the invention to protect the work carrying magnets from the effects of the heat of the furnace. It is also an object of the invention to provide means to remagnetize the magnets from time to time while they are being used,. if

such is necessary.

The various features of novelty which characterize my invention are pointed out with particularity in the claims annexed to and, forming a part of this specifica tion. For a better understanding of the invention, however, its advantages and specific objects attained with its use, reference should be had to the accompanying drawings and descriptive matter in which I have illustrated and described a preferred embodiment of the invention.

In the drawings: v Figure 1 is a side view of the entire machine;

16 so that'the burnerscanbe adjusted individually to produce the proper' heat pattern Normally the temperature of the furnace is controlled automatically by adjusting a'valve- (not shown) in the main supply pipe 15, in response to furnace or worktemperature. The

burners arearranged, as bestshown in Figure 2,'with two burners on one'side'and one burner on the opposite side. In the next lower row of burners there'will be two burners below the one shown in solid lines in the drawing, and one burner below thetwo shown in' solid lines.

'Thus' the burners are placed in the furnace walls in a staggered relation so that the portion of the work projecting'into the furnace will be evenly heated and with- It is noted that a greater or smaller out hotstreaks. number ofburners may be used depending 'upon the lengthof the work that extends'into the furnace and'the' temperature to which the work is to be heated. In any event, regardless of the number of burners'that are used,

the burners of different layers will be staggered with respect to each other as shown in the drawing so that the work -will be heated evenly.

On each side of the slot'through which the work extends into the furnace there is provided a water-cooled heatshield 17 inthe form of a rectangular casing extending the full length of the 'slotof the furnace. Each of the casings is provided with an inlet18 at the bottom thereof and an outlet 19 atth'e top so that water orother cooling fluid may be circulated through it. These heat shields protect the portion of the work that does not extend into the furnace and the conveying-mechanism,

.which will now be described;

The conveying mechanism 3 includes a pair of parallel roller type chains 21, corresponding lines of which are joined together by bars 22 of nonmagnetic material. These chains and their associated mechanism are guided through a predetermined path by sprockets over which the chains pass. As shown in the drawing, a portion of the conveyor travels through a vertical path in front of and parallel to the furnace slot 8 which portion is determined by sprockets 23 and 24. From the sprocket 24 the conveyor travels downwardly and rearwardly around sprockets Z5, and then upwardly to again pass over sprockets 23.

The sprockets 23 are attached to a shaft 26 that is journaled for rotation in bearings 27 mounted on top of a frame of structural steel members that actually form a portion of the frame 1 upon which the furnace is mounted. In alike manner, the sprockets 24 are mounted on a shaft 28 that is journaled for rotation in bearings 29 which are also mounted on the frame. It is noted that the frame includes members 31 which extend be- 1''.

tween sprockets 23 and 24 to guide the vertical run of the conveyor, while structural members 32 extend between sprockets 23 and 25 to guide and back up the upwardly sloping run of the conveyor.

The lower sprockets 25 are mounted on a shaft 33 that is journaled in bearings 34. The bearings for this shaft can move vertically in guides 35 for the purpose of taking up any slack that may appear in the conveying mechanism. The bearings 34 are continuously biased down- Wardly by the weight of the driving mechanism for the J;-

conveyor. For this purpose one end of a rod 36 is attached to the lower side of bearing 34 and its other end is fastened to the upper portion of a bearing 37 that also slides in the guides 35. The bearing 37 and a similar bearing on the other side of the conveyor have journaled in them a shaft 38 upon which is mounted a platform 39. The platform carries the conveyor driving mechanism including a suitable electric motor 41 and a speed reducing unit 42. The motor support 43 is slidably mounted on the platform 39 and has a. portion thereof engaging a threaded shaft 44 that is journaled for rotation, without axial displacement, on the platform. A hand wheel 45 on the end of the shaft 44 is used to rotate this shaft and move the motor toward or from the gear reducer As the motor is moved the diameter of an expansible pulley 46 on its drive shaft is changed to vary its effective speed This pulley drives a belt 47 that in turn drives a pulley 48 on the input shaft of the speed reducer The output shaft of the speed reducer has a sprocket 49 on it which serves to drive a chain 51 that passes over a suitable sprocket 52 attached to shaft 33.

In the operation of the drive mechanism, motor 41 is adjusted with respect to the speed reducer in order to obtain the correct speed of the output shaft of the reducer. This shaft then drives conveying mechanism through the chain 51. The entire platform 39 may be moved around shaft 38 until the chain 51 is under the proper tension. The platform is then fastened with respect to the shaft in order to maintain this tension on the chain. The weight of the platform and the parts mounted thereon is sufficient to maintain the conveying chains 21 at all times under sufficient tension to remove any slack from the mechanism and thereby provide a smooth, steady movement to the parts thereof.

As pointed out above, the conveyor includes two spaced link type chains that pass over the respective sprockets which guide it through its path of travel, and each of the links of one chain is connected with a corresponding link of the chain on the other side of the conveyor by means of a bar 22 that is made of brass or some other nonmagnetic material. These bars each have attached to them a pair of work supports in the form of U-shaped permanent magnets 53. The magnets, as shown best in Figure 3 of the drawing, are attached one at each end of each of the bars 22 extending between chains 31. Each of the upstanding arms of each magnet have mounted upon them a pole piece 54 that is formed with a V-notch '55 in which the work W is received. During the operbers 56 which are rigidly attached to the frame of the machine and extend verticaily upward in a position within the U of the magnets so that they are between the cross-piece of the magnets and the work that is carried thereby. Thus as the chain moves from its vertical run to the portion thereof sloping toward the right the work wiil be stripped by the vertical members 56 from the magnets and will roll down members 57 forming a discharge chute to a point of use.

it is well-known that metals will lose some of their magnetism when they are heated above their curie point. While the heat shields 1'7 serve to protect the magnets from the heat of the furnace it is also desirable to provide a cooling means that is closer to the magnets than the heat shields. To this end one or both of the rectangular ".ernbers 56 may be used as a cooling means. Usuallythe magnet remote from the furnace will not be heated, but the magnet closest to the furnace or on the right of the conveyor in- Figure 2 should be protected from the heat. Accordingly there is provided a supply pipe 53 for a cooling medium that is forced in the bottom of the member 56. Located in the member is a second pipe 59 whose upper end is adjacent to the top of member 56. When the cooling medium, usually water, fills the member 56 it can overflow through pipe'59 and be re} moved. Thus water is circulated continuously within the U of the magnet to remove heat from this assembly during the time that the machine is in operation.

t is desirable in the operation of any machine of this type that the work supporting members are at substan tially the same temperature when a new piece of work is placed thereon for heating. The reason for this is that a machine of this type is designed to heat work from ambient temperature to a predetermined elevated temperature and changes in the temperature of a work support from ambient can affect the temperature of the work. In addition to the above, with a machine of this type it is desirable to make sure that the temperature of the holding magnets is brought back to ambient after it 7 has passed in front of the furnace and before a new piece of work is placed thereon. For this purpose there is provided a tank 61 that is located below the sprockets 25 so that the ends of the magnets will dip into a cooling medium that is circulated in this tank and, therefore, cool the magnets to a predetermined low temperature prior to the time that work is again placed thereon during their upward path of travel.

Ordinarily the cooling means including the heat shield 17 and the stripping members 56 are suflicient to keep the magnets at a low enough temperature so that they will not lose their magnetism. particularly severe heating requirements, and from time to time in other installations it may be desirable to remagnetize the magnets. This can be accomplished as the machine is running byan automatic remagnetizing mech anism of conventional design. Such a mechanism is indicated at 62 as being fastened to the frame of the machine in the path of movement of the magnets. As the magnets move through this device they can be remagnetized to bring them up to their full strength.

In the operation of this machine the burners of the furnace are lit and the furnace chamber is heated thereby both as a result of radiant heat directly from the cups of the burners themselves as well as by the products of In installations having combustion which are released in the furnace chamber. It is noted that the vertical position of the furnace is highly desirable in a machine of this type since thehot products of combustion will rise and escape through the slot provided at the top of the furnace rather than by being blasted out of the slot in front of the furnace and thereby unduly heating the conveying mechanism and the Work holding magnets thereon. The drive mechanism is started and the'work W placed against the magnets from a supply thereof which is indicated diagrammatically at 63. A piece, of work, shown herein as an elongated bar,

is placed in the notches 55 of each of the magnet pole pieces 54 as the magnets are moving to carry them upwardly. 'The work then moves downwardly through the furnace where the endof the work is broughtup to me proper temperature. As the work leaves the furnace it is automatically stripped from the magnets and passes down the chute 57 to a point of use. During the time that the heatingis taking place the magnet work supports are kept at a temperature below a point where their magnetism will be aflected. The use of magnets oft'he type disclosed herein for holding workiis believed to be new with .me. Such work supports are highly advantageous since they will position the work definitely with respect to the furnace and they do not require any mechanical manipulation of the work or the holder in order to place them in position. Attention is also called to the novel manner in which the conveyor driving mechanism is used to maintain at all times the conveyorchain under the proper tension. 7 1

While the work shown herein is in the form of a solid bar it will be obvious that the ends of tubes of other structural shapes may also be heated. The only change necessary will be to shape the notches of the pole pieces so that they will receive the work that is to be heated.

While in accordance with the provisions of the statutes, 1 have illustrated and described the best form of embodiment of my invention now known to me it will be appar ent to those skilled in the art that changes may be made in the form of the apparatus disclosed without departing 7 from the spirit and scope of the invention, as set forth in the appended claims, and that in some cases certain fea tures of my invention may beused to advantage without a corresponding use of other features. I 1

What is claimed is: t

1. For use with a machine for heating elongated work including a vertically extending furnace having anelongated opening in one side thereof through which an end of each piece of work can extend to be heated, apparatus including in combination a conveyor upon which the work is mounted, means to guide the conveyor in a path including a vertically disposed portion and a portion sloping in one direction away from the vertical with the vertical portion thereof adjacent to said furnace opening, a plurality of U-shaped permanent magnets on said conveyor, each magnet having a pole piece on each end thereof against which the Work is placed with the end of the work extending through said opening, cooling means adjacent to said conveyor and between it and said opening to protect the magnets from the heat of said opening, and means extending vertically in the U of said magnets from below said sloping portion, said last means serving to strip the work from said magnets as the conveyor moves from the vertical to the sloping portion of its path.

2. The combination of claim 1 in which said means extending in the U of the magnets is hollow, and means to pass a cooling fluid through said means.

3. A device for use with a machine for heating elonw said conveyor through a path having a vertical portion in front of said-openinga portion slopingin one direction below said vertical portion and a portion sloping in the opposite direction connecting said other two portions, a plurality of permanent magnets on said conveyor to hold the work pieces thereon with an end of each work piece extending, into said opening, cooling means adjacent to said conveyor and between it and said opening in the vertical portion of its path to protect the magnets from theheat, means adjacent to the lower end of the vertical portion of said 'path' to strip the work from said I opening in one side thereof through which the work is r to be moved-comprising in combination means includ-' ing a flexible conveyor upon which the workis mounted,

guiding means includinga plurality of direction ,changing members over which the conveyor passes as it moves work to and from the furnace, means to mountsome of said guiding means in a fixed position to determine the I path through which the conveyor moves, means to mount one of said guiding rneansfor movement ina-direction to take up slack in said conveyor, mechanismtodrive said conveyor, movable monnting means for said driving mechanism below, said movable guiding means, and

means to. connect said mounting means to said movable guidingmeans to bias the guiding, means in a direction to take upslack in said conveyor. a

g '5. Apparatus for use with'a machine fo r heatin' g the ends of bars and the'like including a furnace having a'n elongated opening through which the end of a bar can be moved, comprising incombination a conveyor to, move thebar pastthe furnace with its end therein, means to guide said conveyor .so that it follows a path having a first j portion thereof parallel to said opening and a' second portion extending in a loop from one end of said'openingto the other end thereof, means to drive'said conveyor,

a plurality of permanent magnets .on said conveyor each having a'po le piece extending substantially perpendicular to the path of the conveyor, said pole pieces having ends adaptedto holdsaid bars imposition thereon with the ends thereof in a position to extend into said opening, means extending along the sides of said conveyor .and between said opening and said magnets to protect said magnets from the heat of the furnace, said magnets being .U-shaped with the barsengagi'ng the ends of the mag-. nets, and meansextending within the U of said magnets along the first'portion of said path to strip the bars there be moved, comprising in combinationa conveyor to move the bar past the furnace with its end therein, meansto guide said conveyor so that it follows a path having a first portion thereof parallel to said opening and a second portion extendingin a loop from one end of said opening to the other end thereof, means to drive said conveyor,'a plurality of permanent magnets 'on said con veyor each having a pole piece extending substantially perpendicular to the path of the conveyor, said pole pieces having ends adapted to hold said bars in position thereon with the ends thereof in a position to extend into said 3 opening, means extending along the sides of said conveyor and between'said opening andsaid magnets to protect said i 8. Apparatus for use with a machine for heating the ends of bars and the like including a furnace having an elongated opening through which the end of a bar can be moved, comprising in combination a conveyor to move the bar past the furnace with its end therein, means to guide said conveyor so that it follows a path having a first portion thereof parallel to said opening and a second portion extending in a loop from one end of said Opening to the other end thereof, means to drive said conveyor, a plurality of permanent magnets on said conveyor each having a pole piece extending substantially perpendicular to the path of the conveyor, said pole pieces having ends adapted to hold said bars in position thereon with the ends thereof in a position to extend into said opening, means extending along the sides of said conveyor and between said opening and said magnets to protect said magnets from the heat of the furnace, means to remagnetize said magnets, a work loading station, and means to locate said remagnetizing means at a point along the second portion of the path of said conveyor in front of said work loading station whereby the magnets may be remagnetized as they are moving through the path of the conveyor before work is again placed upon them.

9. Apparatus for use with a machine for heating the ends of bars and the like including a vertically disposed furnace having an elongated slot in the side thereof through which bars can be moved to be heated, comprising combination an endless chain type conveyor having a pair of parallel chains, means to mount said conveyor for movement through a path having a portion thereof parallel to and in front of said opening, a plurality of magnets on each chain of said conveyor to hold the bars thereon, the magnets on one chain being so aligned with the magnets on the other chain that a bar held by a magnet on each chain will extend substantially per pendicularly into the opening of the furnace, means to drive said conveyor whereby bars will be moved one after the other through said furnace, said magnets being U- shaped, a pair of stripping members, means to mount saidmembers to extend in the U of the magnets along the portion of the path thereof in front ofsaid furnace, and means to guide said conveyor at an angle to said path in a direction opposite to the legs of the U as it leaves said portion of said path to thereby strip the bars from said magnets.

10. The combination of claim 9 in which the stripping member in the row of magnets nearest the furnace is hollow, and means to supply a cooling fluid through said member.

References Cited in the file of this patent UNITED STATES PATENTS 

1. FOR USE WITH A MACHINE FOR HEATING ELONGATED WORK INCLUDING A VERTICALLY EXTENDING FURNACE HAVING AN ELONGATED OPENING IN ONE SIDE THEREOF THROUGH WHICH AND END OF EACH PIECE OF WORK CAN EXTEND TO BE HEATED, APPARATUS INCLUDING IN COMBINATION A CONVEYOR UPON WHICH THE WORK IS MOUNTED, MEANS TO GUIDE THE CONVEYOR IN A PATH INCLUDING A VERTICALLY DISPOSED PORTION AND A PORTION SLOPING IN ONE DIRECTION AWAY FROM THE VERTICAL WITH THE VERTICAL PORTION THEREOF ADJACENT TO SAID FURNACE OPENING, A PLURALITY OF U-SHAPED PERMANTNT MAGNETIS ON SAID CONVEYOR, EACH MAGNET HAVING A POLE PIECE ON EACH END THEREOF AGAINST WHICH THE WORK IS PLACED WITH THE END OF THE WORK EXTENDING THROUGH SAID OPENING, COOLING MEANS ADJACENT TO SAID CONVEYOR AND BETWEEN IT AND SAID OPENING TO PROTECT THE MAGNETS FROM THE HEAT OF SAID OPENING, AND MEANS EXTENDING VERTICALLY IN THE U OF SAID MAGNETS 